Underwater current turbines are used in tidal or ocean current systems in order to extract power from the marine energy. Such turbines can also similarly be used in rivers. Such underwater current turbines are installed floating or directly on the sea floor/riverbed and have large similarities with wind turbines, however they are still in the development stage. They often have large dimensions and are situated in inaccessible areas. However, standard designs that would reduce the costs for such power plants are not available. Moreover, underwater current turbines can place high demands on the seals to realize an underwater current turbine with connected generator nacelle. Thus conventional underwater turbines, as described, for example, in DE 10 2014 204 593, have methods of construction wherein a shaft driving the generator is enclosed by a sleeve by which in turn the rotor blades are supported in order to minimize water entry. Here the external rotor sleeve is supported against an outer surface of the generator nacelle, which outer surface extends over the main shaft toward the rotor and is separately supported.
However, it is disadvantageous with these underwater current turbines known from the prior art that a variety of separate bearings is required in order to support both the external rotor sleeve and the rotor shaft. In addition, the proposed bearings are subjected to high loads and must additionally endure saltwater entry, which greatly reduces the service life of the bearing. Furthermore it is disadvantageous that an exchange of the bearings is only possible individually and with complete disassembly of the entire underwater current turbine, which is very time and cost intensive.